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Coughs and sneezes spread diseases: but do ‘aerosol generating’ procedures?
  1. David T Arnold1,
  2. Fergus W Hamilton2,3,
  3. Ed Moran4
  1. 1 Academic Respiratory Unit, University of Bristol, Bristol, UK
  2. 2 MRC-IEU, University of Bristol, Bristol, UK
  3. 3 Microbiology, North Bristol NHS Trust, Westbury on Trym, UK
  4. 4 Department of Infectious Disease, North Bristol NHS Trust, Bristol, UK
  1. Correspondence to Dr Ed Moran, Department of Infectious Disease, North Bristol NHS Trust, Bristol BS10 5NB, UK; Ed.moran{at}

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The COVID-19 pandemic has led to the widespread use of continuous positive airway pressure (CPAP) and high flow nasal oxygen systems (HFNO) for respiratory support, with the former recently shown to reduce the requirement for intubation and mechanical ventilation, easing pressure on intensive care and improving outcomes.1

One major concern remains the theoretical risk for aerosolisation of SARS-CoV-2, with both CPAP and HFNO currently considered ‘aerosol generating procedures’ (AGPs). This classification, endorsed by Public Health England, the WHO and US CDC, dichotomises medical procedures into those that potentially generate infectious aerosol (smaller particles, generally <5 µm with the potential to remain suspended for extended periods) and those that do not.2 Enhanced infection control precautions (eg, airborne mask protection, increased ventilation, cohorting) are thus advised when patients undergo AGPs but are not mandated outside these settings.

The evidence supporting this concept of AGPs is largely based on epidemiological observation, particularly from the SARS pandemic, with limited physical data supporting the role of aerosol generation in most AGPs.3 Studies conducted over the course of the pandemic are undermining the AGP paradigm, with convincing evidence that …

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  • Contributors DTA and FWH produced a first draft. EM then extended and developed it.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Provenance and peer review Commissioned; externally peer reviewed.

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